Patent GB-469949-A (GB)
Title: Process and apparatus for inspecting fluids
IPC: G01N21/90
Filed: 1936-02-05
Abstract: 469,949. Photo-electric apparatus for inspecting liquids in containers. STOUT, G. P. Feb. 5, 1936, No. 3416. Convention date, Feb. 5, 1935. [Class 40 (iii)] Liquid in a container is inspected for the detection of solid matter &c. in the liquid by passing light through the liquid to a photoelectric cell, and so arranging the amplifying circuit of the cell that electrical impulses are produced by the abrupt change in the photoelectric current due to the presence of solid particles in the liquid. In the apparatus described, a series of containers are passed in succession between the light-source and the cell and the impulses are caused to control means whereby any container in which solid matter is detected is rejected. Means are provided for setting the containers in rotation as they approach the source of light and then for quickly stopping them so that the liquid is rotating within the stationary container while the light passes through it. The form shown comprises an endless intermittently-driven conveyer 30 receiving bottles 34 from an input wheel 33 to which the bottles are supplied by a conveyer 36. The bottles are carried on the conveyer 30 in cups 38, each of which is rotatably mounted in a plate 37 and carries a roller 41 adapted to be engaged by a series of rollers 42, Fig. 4, of progressively increasing diameters, driven by a common. shaft 43, so that the bottle receives rotary motion of increasing velocity as it moves along with the conveyer 30. When the bottle has acquired its maximum rotation it is received by a brake 47 which brings it to rest, leaving the liquid contents in rotation within it. In this condition the bottle passes in front of a light-source 60, Fig. 14, provided with condensing lenses 61 for projecting light through a slit 63 and through the bottle to a focusing device 65 from which the light passes to reflecting prisms 69 which direct it to photo-electric cells 66, 67, 68. A second conveyer 49, moving synchronously with the conveyer 30, is provided with a number of plates 56 carrying caps 57 which fit over the mouths of the bottles and retain them in vertical position. The cells are arranged in an amplifying circuit in such a way that an abrupt reduction in the photo-current, due to obstruction of the light by solid matter in the liquid content of a bottle, produces an electrical impulse which completes the circuit of a stationary solenoid 70, Fig. 11. Each of the plates 56 carries a slidably-mounted pin 71 and the action of the solenoid 70 is to eject the pin pertaining to the bottle in which the solid matter is present, the pin being held in its ejected position by a catch 72. When the defective bottle reaches a position in which is about to be delivered by the output wheel 78, the ejected pin 71 is adapted to complete the circuit of a solenoid 75 which then moves a pivoted gate 77 to the position shown in Fig. 3 in dotted lines, so that the bottle is delivered to the rejection conveyer 79. A cam is provided to release the catch 72 after the solenoid 75 has been actuated, the pin 71 being then restored to its initial position by a spring 202. The electrical circuit includes relays which operate to ensure the rejection of all bottles if a defect should occur in the apparatus. A modification is described in which the bottles are mounted on a continuously rotated circular carrier and the light source &c. is oscillated so as to be stationary relatively to each bottle in turn while the light is being projected through the bottle.